BRIAN URLACHER wasn't sure how dominant he could be any longer, so he is retiring after 13 seasons with the Chicago Bears. And what a career it was: eight Pro Bowl seasons; defensive player of the year in 2005; a trip to the Super Bowl as 2006 NFC champion.

And now, it's over. Urlacher, 34, announced his retirement through social media accounts yesterday.

"After spending a lot of time this spring thinking about my NFL future, I have made a decision to retire," Urlacher said in a statement. "Although I could continue playing, I'm not sure I would bring a level of performance or passion that's up to my standards. When considering this, along with the fact that I could retire after a 13-year career wearing only one jersey for such a storied franchise, my decision became pretty clear."

Urlacher ranks among the best middle linebackers to suit up for a franchise with an impressive list that includes Hall of Famers Bill George, Dick Butkus and Mike Singletary.

In March, Urlacher and the Bears were unable to reach a contract agreement and he became a free agent. He started 180 games from 2000-2012, and made a team-record 1,779 tackles. He had 41 1/2 sacks, 22 interceptions, 16 fumble recoveries and 11 forced fumbles.

Noteworthy * 

San Francisco 49ers leading wide receiver Michael Crabtree had surgery to repair a torn right Achilles' tendon.

Crabtree was operated on yesterday, a day after suffering the injury during an OTA. Coach Jim Harbaugh would not speculate when Crabtree might return to play, but the injury is not necessarily season-ending.

Crabtree, 25, the team's 10th overall pick in the 2009 draft out of Texas Tech, had career highs last season with 85 receptions for 1,105 yards and nine touchdowns.

* Commissioner Roger Goodell said at the spring owners meetings in Boston that the league is discussing cutting two preseason games and either expanding the playoffs or going to an 18-game regular season.

Goodell also confirmed that the 2014 draft will be moved from April to May, sometime between the 8th and 17th.

* New York Jets rookie quarterback Geno Smith has chosen rap artist Jay-Z's new Roc Nation Sports to represent him. Smith, who slipped out of the first round last month and fell to the Jets in the second round at No. 39 overall, fired his agents - Select Sports - shortly after the draft.

* St. Louis offensive lineman Rokevious Watkins has been suspended without pay for the season opener for violating the NFL's substance-abuse policy.